CRYOSTAT, ALCOR LIFE EXTENSION FOUNDATION, ARIZONA
A cryostat is filled with liquid nitrogen at Alcor. The cylinders work in the same way as a Thermos flask: a vacuum insulates the inside from the outside. “It’s difficult to keep them 100 per cent insulated and a certain amount of liquid nitrogen gradually boils off,” Ballard says. “They get topped up once a week.”